The humidity at each layer in the low atmosphere in the stations of ningxia can be retrieved with pretty high accuracy using the non - linear models above . ( 4 ) variation and quality control : a ) . the retrieved relative humidity at different stations was expanded into the grids with variational method to match the meso - scale numerical weather forecast model mm5v3 for heavy rain forecast , b ) 试验表明,使用本文的反演方法,利用地球同步气象卫星红外资料对各层大气相对湿度进行反演,并进行变分、质量控制,在中国西北宁夏这样一个干旱地区,可以提高中尺度数值预报模式对强降水的预报能力。
The results indicate that : only with a few rain gauges to adjust the radar estimated rainfall , authors could simulate the runoff as good as that from rain - gauge - network - measured rainfall ; the accuracy of radar rainfall estimation to heavy rain acts as a more important role than that of light rain ; the estimation error of amount precipitation over a period can be treated as an index for runoff simulation ability 在1500小时时间序列的比较试验表明,雷达估测面雨量和雨量计测量的面雨量都能较好地模拟每小时流域出口蒋集的出流量,数值试验还表明,雷达估测面雨量在某一时段上的均值误差作为一个指标可以较好地反映其应用于降水径流模拟时的精度总雨量和强降水的估测精度是雷达估测面雨量能否用于径流模拟的关键。
Mm5 adjoint - model assimilation system not only can improve the initial field effectively and promote the coordination with the model but also can enhance the forecast on the precipitation and other elements . the assimilation of cdw has an improvement on quality of upper wind . the effect of direct numerical simulation with utilizing the cdw to amend the initial field gains the advantage over the one not 结果表明, mm5伴随模式同化系统能有效改善初始场与模式的协调能力,提高模式对于降水场和其它要素场的预报;使用云导风资料修正初始场后直接模拟的效果比未使用时直接模拟的效果要好,对部分区域的强降水预报精度有一定程度的改善;使用伴随模式同化系统后,加入云导风资料的同化试验对其它要素的改善与直接同化常规资料的效果相比,改善优势不明显,但从各要素的误差来看,对于风场的改善最好。
We can use the mm5 model in definite time , definite area weather forecasting . we conclude that : : the moving route of this necw in its developing progress was direct - south along latitude , the cold air is rough , and just this made the rough vertical velocity ; the necw southern moving and conflicting with the west pacification sub - tropical high makes rough jet steam . the plenty south - west warm and wet air made by the jet stream gave the rainstorm demanded vapor ; . the rough vertical velocity by jet stream is a main reason in this rainstorm ; the mm5 model uses four - direction analysis data as its input , this avoids some errors occurred in observe and transfer , thus made the result more useful 综合分析认为: ( 1 ) 、这次冷涡在其发生发展过程中,其移动路径是沿经圈直线南压,携带的冷空气势力较强,形成槽后较强的垂直运动; ( 2 ) 、西太平洋副热带高压偏北位置与东北冷涡南压形成的急流轴,把源源不断的西南暖湿气流输送到辽西地区,也就是急流轴的左前方位置,为这次暴雨的产生提供了充足的水汽来源; ( 3 ) 、低空急流不但为暴雨输送水汽,其造成的较强的垂直环流也是产生强降水的一个主要原因; ( 4 ) 、 mm5模式以四维同化资料作为初始场,最大限度地避免了观测误差可能造成的积分不稳定,提高了模拟结果的参考价值。
2 ) the analyse of the structure of mei - yu low and the elationship between the low and rainfall three lows moved along the mei - yu front towards the northeast during mei - yu period in 1999 , which produced three intensive rainfall periods along the yangtze river : ill the station of huangshan , the most heavy rainfall center , totally had 850mm rain during 11 days . the reason for the heavy rainfall was the sustaining moisture supply from the south , and the deep moist layer and the high relative humidity in the south - east quadrant 2 )梅雨锋低涡的结构及其与降水关系分析1999年在梅雨锋上有三个梅雨锋低涡相继在其上产生,冰箱东北方向移动,分别对应着长江中下游的三次强降水过程:最大降水中心黄山11天累计降水量达到850mm ,为梅雨期间平均降水量的150以上。低涡之所以产生这么大的降水和降水强度是因为低涡在移动过程中不断有水汽输入和补充,在其东南象限对流层中低层维持了深厚的湿层和很高的相对湿度。